A lorry struck the railway bridge on Springfield Road in the early hours of Saturday morning.
The incident happened at about 4am. A spokesman for Network Rail said there was no damage to the bridge.
The spokesperson said: “At around 4am on Saturday, a Network Rail worker reported that a lorry had struck a railway bridge on Springfield Road in Grantham. Network Rail engineers visited the site and carried out an inspection of the bridge shortly after 6.10am. No repairs were needed.
“We cannot stress enough how important it is that drivers know their height of their vehicle and plan their routes ahead of time, to prevent incidents like this happening. In the past five years, three rail bridges in Grantham have been struck over 130 times, causing the equivalent of over nine days of delays to road users and rail passengers.”
Traffic was very heavy during the day in the town. Motorists have told the Journal that Springfield Road was still closed later into the afternoon.